$CM_{\mathrm{X}-\text{Ray}}$: An X-Ray Compatibility Metric for Advanced Packages to Facilitate Design-for-Inspection

During the pre-silicon stage, being able to predict the compatibility of an integrated circuit (IC) package to X-ray based inspection can be crucial in modern semiconductor manufacturing and post-silicon validation. This is particularly significant as the industry progresses towards more sophisticated packaging technologies, driven by the emergence of heterogeneous integration. X-ray inspection is commonly employed for failure analysis and defect localization, but its effectiveness can vary depending on the design's feature size and complexity. The intricate, densely packed, and noise inducing features in an advanced IC package such as micro-bumps, TSVs, RDL
^se
tc. can hinder the process of image acquisition and reconstruction using X-ray tomography or laminography. This work addresses the importance of a compatibility metric, and proposes the development of
$CM_{\mathbf{X}-\mathbf{Ray}}$
, a metric that, in the pre-silicon stage, provides chip designers with an estimation of how well they can observe the fine-pitched features in advanced IC packages through X-ray inspection.